1. Field of the Invention
The present invention relates to an automatic steering apparatus for a hay rake, such as a collapsible pull type V-shaped rake for gathering hay.
2. Background Art
Hay rakes, such as V-shaped hay rakes having two movable arms which carry multiple rake wheels, are typically moved and operated by means of a towing vehicle, such as a tractor. For instance, a hay rake is usually equipped at its front end with a coupling element, e.g., an eyelet, for attaching to a corresponding coupling element on the towing vehicle. Typically, the towing vehicle, when coupled to the hay rake, provides motive power for towing the hay rake, so as to eliminate the need for the hay rake to have motive power of its own. In addition, the towing vehicle is typically steerable, while the hay rake is not. It is usually deemed sufficient that the steering of the towing vehicle will provide adequate steerability of the hay rake being towed therebehind. However, hay rakes are often very large devices. Thus, a hay rake may travel a considerable distance before it changes its direction of travel in response to a change in the towing direction of the towing vehicle. This considerable distance may be undesirably large
Therefore, there is a need for a towable hay rake having improved maneuverability.
The present invention, according to one embodiment, relates to a hay rake towable by a towing vehicle. The hay rake includes a front portion, such as a separate carriage section, connectable to the towing vehicle. In addition, the hay rake includes at least one wheel, but preferably two wheels, mounted to, e.g., a rear end, of the hay rake. The hay rake also includes an automatic steering mechanism. The automatic steering mechanism is coupled to the front portion of the hay rake and is configured to be actuated by a change in towing direction of the towing vehicle. The automatic steering mechanism is further configured upon actuation to steer the at least one wheel. According various embodiments, the automatic steering mechanism may be configured to steer any wheels of the hay rake, regardless of the position of the wheels on the hay rake.
According to one embodiment of the present invention, the automatic steering mechanism comprises at least one rotatable element and at least one longitudinally-movable element configured to rotate and/or move upon a change in towing direction of the hay rake. The rotatable element and the longitudinally-movable element are coupled to and configured to cause a first cross member, which is coupled to the wheels of the hay rake, to move in a direction corresponding to the change in towing direction of the hay rake. Advantageously, the wheels of the hay rake are mounted on opposite, e.g., left and right, sections of a second cross member at a rear end of the hay rake. The first and second cross members may be extendible and retractable, preferably in synchronous fashion, by hydraulics or manually. In one embodiment, left and right sections of the first and second cross members are extendible and retractable by corresponding dual action hydraulic actuators, the operation of each dual action hydraulic actuator being controlled by a power divider valve that is configured to divide an actuating hydraulic fluid between the first and second hydraulic actuators. The dual action hydraulic actuators may also be coupled to stop valves that block movement of the corresponding hydraulic actuators when actuating hydraulic fluid is not being supplied to the corresponding hydraulic actuators.